POWER AND LINEAR IC SOLUTIONS

Switching Regulator Drives High Brightness LEDs

The NCP3066 from ON Semiconductor is a monolithic switching regulator designed to deliver constant current for powering High Brightness LEDs (HBLEDs).



Primarily intended for use in lighting applications, an automotive version of NCP3066 is available and the device is also useful for unregulated supplies, such as rechargeable batteries.

The NCP3066 has a very low nominal feedback voltage of 235mV, which it uses to regulate the average current of the LED string. This allows the use of a small, low cost, external sense resistor. Additionally, the device’s wide input voltage, up to 40V, allows it to operate from a 12VAC or 12VDC supply in line with the requirements of its target applications.

The regulator can be configured in step down (buck), step up (boost) and voltage inverting topologies with a minimum number of external components. An integral 1.5A switch allows the construction of small footprint systems. The ability to operate with all ceramic output capacitors, or no output capacitance, further reduces solution size.

The NCP3066 operates at an adjustable frequency up to 250kHz, allowing engineers to optimise their designs for efficiency and size. It features internal thermal shutdown with hysteresis and includes an on/off pin for direct PWM dimming at up to 1kHz. The device can be placed in a low power, standby mode that draws a current of less than 100µA.

The device is available in eight pin, narrow bodied SOIC, DFN or PDIP packaging.

Features

• Buck, boost, invert regulator for HBLEDs
• Integrated 1.5A switch
• Wide input voltage range: 3V to 40V
  • Allows operation from 12VAC or 12VDC supplies
• Low feedback voltage: 235mV
• Cycle by cycle current limit
• Frequency adjustable up to 250kHz
• No output capacitor required
• Internal thermal shutdown with hysteresis
• On/off pin for direct PWM dimming
• Low current standby mode: less than 100µA

Applications

• Constant current source
• High power LED driver
• High brightness LEDs

For further information, including the ON Semiconductor NCP3066 Datasheet, please click here